Further development of a Lipoprotein Analyzer based on flow field-flow fractionation (Flow FFF) is proposed. Flow FFF is an innovative technology capable of high resolution separations. This methodology is gentle, flexible and biocompatible for analysis of biological macromolecules ranging from proteins to cells. The driving force for separation is generated via application of an external field -- in this case, a cross flow field. External application allows the separation to be easily tuned for desired resolution / analysis time. Thus, Flow Fff is a powerful and effective tool for rapid, direct measurement of each subfraction of the lipoprotein profile. Phase I work successfully demonstrated separation of HDL, LDL, and VLDL components in human blood plasma. Recovery rates were comparable or better than that of traditional ultracentrifugal technique. Analysis times were on the order of 20 minutes per sample. System cost < $30,000. Phase II is directed at further demonstrating accuracy and precision, increasing sample throughput, and streamlining system design / operation for user convenience. The overall result of this work will be an inexpensive direct technique for simultaneous quantitation of HDL, LDL, and VLDL components in human blood plasma. Patient fasting will not be required as triglyceride levels are not involved in the measurement. PROPOSED COMMERCIAL APPLICATION: Current techniques for screening serum cholesterol are indirect or otherwise inadequate. The proposed system will provide a rapid, direct, low cost alternative to current techniques. Patient fasting will not be required. The specifications & design of the proposed system considers commercial needs of lipoprotein research & centralized clinical labs as well as needs for increased precision, accuracy, & reliability.